The present disclosure relates in general to the technical field of electrohydraulic brake force generating devices. It relates in particular to an electromechanical brake force booster which can be used in an electrohydraulic brake force generating device.
Electromechanical brake force boosters are driven by electric motors. In order to be able to produce a boosting of the brake force with the brake force booster, the rotational movement of the output shaft of the electric motor has to be converted into a translatory movement. For this purpose, various devices are known from the prior art.
WO 2014/177691 discloses a brake system with a main brake cylinder and a servo brake. The servo brake has an electric motor, the driven shaft of which bears a screw. The screw drives two helical gearwheels. The helical gearwheels are each connected to a spur gear via a shaft. The spur gears each drive a rack in order to be able to move a thrust rod for actuating the main cylinder.
Document WO 2011/003643 A1 discloses a force transmission arrangement. The force transmission arrangement has an electric motor which drives a worm shaft. A worm toothing is formed on the worm shaft. The force transmission arrangement furthermore comprises a first worm gear, a second worm gear, a first pinion and a second pinion. A rack has a first row of teeth and a second row of teeth. The longitudinal axis of the rack runs parallel to the axis of the worm shaft. The first pinion meshes with the first row of teeth and the second pinion meshes with the second row of teeth. The first pinion is connected to the first worm gear, and therefore the first worm gear and the first pinion rotate together. In the same manner, the second worm gear is connected to the second pinion. The first worm gear and the second worm gear are jointly driven by the worm toothing on the worm shaft.
An electromechanical brake force booster is furthermore known from the prior art and is disclosed in the document EP 2420421 A1. The electromechanical brake force booster has an electric motor, a thrust rod and a drive device for driving the thrust rod. A drive shaft of the electric motor drives a first gearwheel with an external toothing and a second gearwheel with an internal toothing. The first gearwheel drives a first toothed wheel and the second gearwheel drives a second toothed wheel. The first toothed wheel and the second toothed wheel engage in a toothing on the thrust rod for the translatory driving of the thrust rod.
The devices known from the prior art are relatively large due to their design or their construction. The reason resides, inter alia, in the complex construction of the gearing arrangements described in the documents mentioned for converting a rotation into a translatory movement.